Screening bone marrow derived murine mesenchymal stem cells for tumourigenicity. Mus musculus

To study early events in osteosarcoma genesis murine bone marrow derived mesenchymal stem cells (mMSCs) were studied which generated osteosarcoma-like tumours upon injection into nude mice. The process of transformation was studied in a step-wise manner by culturing the MSCs in vitro for 28 passages. Subsequently the transformed passage 28 MSCs were compared to their normal passage 12 originator cells in a number of experiments to identify underlying events prior to malignant transformation. In addition both low and high passage MSCs were shown to still have the phenotypical and functional characteristics of normal MSCs. Overall design: Previously reported tumourigenic MSCs (TmMSCs) and tumours derived from these cells (T1 and RT2) as well as two new bone marrow derived MSCs cultures from C57BL/6 and BALB/c mice (B6-mMSCs and Bc-mMSCs respectively) were cultured. To characterize the cells FACS analysis and multi-lineage differentiation analysis were performed. To screen for genetic alternations genome wide high resolution arrayCGH (all 7 samples) and COBRA-FISH (for 5 samples) were performed and validated at the gene expression level by qRT-PCR. To look for the clinical relevance of the findings an osteosarcoma tissue array containing human osteosarcoma samples from 88 well-characterized patients was constructed and stained for the relevant proteins by IHC. Correlations with the survival of the patient and other characteristics were analyzed by using SPSS software.